An "Iframe App" refers to a single-window application which simply incorporates a full size <iframe>
element filled to the window content container. Said Iframe will usually point to an external resource (resource not hosted within the Windows 96 environment) and will have very little logic to integrate with the Windows 96 API.
Iframe apps are extremely simple to create, and require little to no effort compared to more complex applications. This is sometimes useful for hosting external content which does not necessarily want to rely on Windows 96 specific APIs.
Criticism
A lot of users and developers are against Iframe apps, since they are extremely easy to code and require almost no knowledge of the Windows 96 API and program structure.
History
The first Iframe App seems to be an API example from v2 probably made by Ctrlz. This app had an iframe pointing to sys36.netand originated from Windows 96 v2 Service Pack 1.
the first community-made Iframe App I(NanderTGA) could find was RecordRTC by Jame AKA ctrli, uploaded in a thread on discord (in the creations channel) to publish packages for Nander to upload to his repository. This package was never uploaded as he either forgot or didn't want to convert the icon to a different resolution.